Spark-plug.



FOREST R. LA PLANEE, 0F GUNNISON, COLORADG.

SPARK-PLUG.

Specification of Letters Patent.

Patented Feb. 2?, 1917.

Application filed September 19, 1916. Serial No. 120,996.

To all 'whom t may concern:

Be it known that l, Fenner LA FLA-inria, acitizen of the United States,residing at Gunnison, in the county of Gunnison and yState ot' Colorado,have invented new and useful improvements in Spark Plugs, ot which thefollowing is a speciiication.

This invention relates to spark plugs 'tor ignition circuits, the broadobject in view bem ing to produce a plug and means used Con- `jointlytherewith, whereby the direction or" iow of the electric current throughthe plug and to the ground may be reversed or caused to travel in theopposite direction for the purpose of maintaining the points of theelectrodes in a clean condition and preventing the accumulation or"material between the same which would ultimately bridge the gap andeliminate the spark.

Vith the above and other objects in view, the invention consists in theconstruction, combination and arrangement, herein fully described,illustrated and claimed.

In the accompanying drawing:

Figure 1 is a diametrical section through a spark plug embodying thepresent invention.

Fig. 2 is a detail perspective view of the primary switch.

Fig. 3 is a similar view of the washer used in conjunction with theswitch.

'F ig. 4t is an end View of the core.

Fig. 5 is a. detail perspective view of the secondary switch.

Fig. 6 is a fragmentary section showing the relation of the secondaryswitch to one of the electrodes.

Referring to the drawings 1 designates the shell or main body of theplug which is externally threaded at 2 to enable the same to be screwedinto an engine cylinder in the same manner as the ordinary spark plugnow in common use. The shell or body 1 may, of course, be madeof anysize and threaded in accordance with any standard spark plug.

The body 1 is counterbored in its inner end to form an annular shoulder3 against which bears the corresponding annular shoulder 4- formedexteriorlv of the core 5 of the plug, said core being composed of anysuitable insulating material such as porcelain, fiber or raw-hide, theshoulders 3 and t preventing the core trom being blown outwardly throughthe shoulde 1 or body 1 when an explosion occurs in the combustionchamber of the cylinder.

rlhe outer end of the body 1 is counterbored and internally threaded asshown at G to receive a packing nut or gland 7, packing material S suchas asbestos being placed in the inner portion of the counterbore of thebody 1 so as to prevent leakage between the core and shell.

Extending longitudinally through the core 5 'and in substantiallyparallel relation to each other, are electrodes 8 and 9 each oil whichmay constitute the power electrode aS will hereinafter appear. At theirinner extremities, the electrodes S and 9 are deiiected toward eachother to leave a gap 10 of any desired width. rhe opposite end portionsof the electrodes are bent or extended outwardly in opposite directionsto 'form contact ends 11 and 12 the same proecting slightly beyond theouter surface of the core 5.

' 13 designates the binding post of the plug and 11i a circuit terminalin electrical contact therewith. 15 represents a binding nut 'for theterminal 14 and 16 represents a am or lock nut, both of said nuts beingthreaded on the binding post 13 the inner end of which is anchored inthe body of the core 5 as shown.

17 represents a switch consisting of apla-te or `disk-like body which isformed with a central hole to receive the binding post 13 and 1Srepresents a nut threaded on the post 13 to prevent the switch fromturning or bearing tightly against said switch. rlfhe switch comprisesan inwardly extending spring arm 19 which normally lies in contact withone of the end portions 11 or 12 of the electrodes S and 9 as clearlyillustrated in Fig. 1. Between the switch 17 and the adjacent end of thecore 5 there is arranged a washer 20 which is held in a certain definiterelation to the core 5 by means of a diametrically extending hollow rib21 .Formed on the washer and having its convex face received in adiametrical seat in the core 5. The switch body 11 is formed with acorresponding rib 2:2 which is received in the groove thus termed in thewasher 20. The switch and washer are thus maintained in a certaindefinite relation to each other and to the end of the core, insuringcontact between the switch arm 19 and one of the electrodes. Byloosening the nuts at the outer end of the plug, the switch 19 may besuflicient] y loosened to be turned by hand through an arc of 1800 forthe purpose of bringing the switch arm 19 into contact with the otherelectrode.

lien the switch arm 19 is in contact with one of the electrodes, theother electrode is in contact with the spring arm 23 of another switchQflthe body of which is in the form of a disk or plate having a centralopening to receive thevcore The end portion of the spring arm 23 ispreferably grooved as indicated at 25 to prevent the same from becomingaccidentally disengaged from the electrode with which it lies incontact. A nut 2G serves to clamp the switch 2st against a shoulder 27on the packing nut or gland 7 hereinabove referred to.

From the foregoing description taken in connection with the accompanyingdrawing, it will now be understood that by shifting the primary andsecondary switches 17 and 24C through an arc of 180o or by turning thecore 5 through the same number of degrees, the direction of flow of theelectric current will be reversed and thereby any particles of carbon,metal or other material which may have accumulated on one of theelectrodes will be forcibly ejected, propelled or driven therefrom,thereby keeping the gap free for the jumping of the spark across thesame. ln this way the life of the plug is greatly prolonged and the samemay be easily maintained at its full efliciency, preserving theelectrical conductivity of the electrodes. The plug may be tested by ascrew driver or other implement 'in the same manner as the present dayspark plug used in conjunction with internal combustion engiiies.

for reversing the direction of iiow of an ignition circuit through saidelectrodes.

2. A spark plug embodying two electrodes insulated from the spark plugcasing and `a-riaiiged to form a spark gap adjacent t0 one end of theplug, a primary switch for conducting the current to one electrode,means for shifting said switch from one electrede to the otliei', andmeans for grounding the electrode not in contact with said switch.

3. A spark plug embodying two electrodes insulated from the spark plugcasing and arranged to-form a spark gap adjacent to one end of the plug,a primary switch for conducting the current to one electrode, means forshifting said switch from one electrode to the other, and means forgrounding the electrode not in contact with said switch, the last namedmeans consisting of a secondary switch adjustable from contact with oneelectrode into contact with the other electrode.

4. The combination of a spark plug having two electrodes insulated fromthe spark plug casing forming a gap adjacent to one end of the plug andhaving their opposite ends extended outwardly through the side walls ofthe plug core, a primary switch adjustable foi-the purpose of conductingthe current to the last named end of either electrede, and a secondaryswitch adjustable for FOREST R. LA PLANTE.

Copies of this patent may be obtained for five 'cents each, byaddressing the Commissioner of Patents, Washington,v D. C.

